The present invention relates generally to containers having a sealed opening, and more particularly to a closure seal for sealing an opening of a container.
Packaging for certain types of products, and for bottled liquid products in particular, often require a seal that is both peelable (i.e., easy one-piece removal) and leak-proof and that retains the freshness of the contents of the container. Once opened, the freshness seal will be broken. It is, therefore, desirable that the seal be adequately and securely retained over the opening of the container prior to removal. However, it is also highly desirable that the seal be easily removable by the consumer of the product.
Many different types of closure seals are known that adequately perform the peeling, leak prevention and freshness seal objectives. Some of these closure seal designs also incorporate some form of structure or device that assists in removal of the seal. Many simple closure seal designs include a tab extending from a peripheral edge of the seal that can be grasped by a user to remove the closure seal from the container. However, it is often difficult for an individual to grip and hold the tab. Moreover, such a tab also requires special die punch equipment to cut the protruding tab. Yet further, the peripherally extending tab can interfere with good sealing due to the need to accommodate the tab in a cap, e.g., by folding over the tab during capping.
More sophisticated examples of pull-tabs are also known.
For example, U.S. Pat. No. 5,433,992 discloses a seal construction wherein a multi-layer seal is formed with each of the layers adhering to one another. However, a portion of the seal includes a non-adhered section to between two layers. The exposed upper portion of this section of the seal acts as a pull-tab that can be gripped by the user to release the seal from the container.
Selig Sealing Products' own U.S. Pat. No. 5,702,015 discloses a closure seal that also has a pull-tab extending from an upper surface of the seal. The seal disclosed in this patent is formed having a first layer and a second layer of the same material that are co-extruded so as to form a single layer with a portion of the layer forming a pull tab. One advantage of this structure is the elimination of possible environmentally sensitive chemicals used in providing adhesive to secure a second layer to for the pull tab as is down in U.S. Pat. No. 5,433,992.
One problem with many of these closure seals and pull-tabs are that the pull-tabs are thin and difficult to grasp. Formation of a thicker pull-tab would improve the removability characteristics of the closure seal. However, it is desirable not to increase the number of material layers in order to accomplish this objective because of material and manufacturing cost concerns. Another drawback associated with many pull-tab constructions is that, during the manufacturing process, adhesives and/or other bonding techniques must be applied to the sheet or blank of material intermittently over specified areas in order to accomplish formation of the pull-tab. These specific and precise manufacturing techniques add expense to the manufacturing and design processes. A further drawback of many pull-tab designs is that only one pull-tab is available for the consumer to grasp. The pull-tab may be inadvertently partly adhered to another portion of the seal and difficult to initially lift and grasp, or may at least initially be difficult to detect.